Spin-orbit coupling in transition metal dichalcogenide heterobilayer flat bands

The valence flat bands in transition metal dichalcogenide (TMD) heterobilayers are shown to exhibit strong intralayer spin-orbit coupling. I show that symmetry constrains the spin-dependent complex phase of hopping terms in an effective tight-binding model of the valence flat bands. A perpendicular electric field causes interlayer hybridization, such that the effective model becomes equivalent to the Kane-Mele model of topological insulators. The proposed model can be used as a starting point to understand interactions and the experimentally observed topological transitions.

Automated summary

This article investigates the valence flat bands in transition metal dichalcogenide heterobilayers, which exhibit strong intralayer spin-orbit coupling. By applying symmetry constraints to a tight-binding model of the valence flat bands, the author demonstrates the spin-dependent complex phase of hopping terms. Additionally, the model becomes equivalent to the Kane-Mele model of topological insulators when a perpendicular electric field causes interlayer hybridization. This proposed model serves as a starting point for understanding interactions and experimentally observed topological transitions.